Five months into World War III, Ellie and her four remaining friends have barely escaped the Australian town of Wirrawee with their lives and their sanity intact. But as the next step becomes clear, they realize they must once again sacrifice their hard-won comfort and safety. Ellie and her friends are asked to guide soldiers from New Zealand through the thick bush to the enemy-occupied Wirrawee air base near their home. What could possibly motivate Ellie and her friends to return? This risky sabotage mission may be their only hope of rescuing their families, too. Will they find the families they left behind, or is it already too late?